This invention relates generally to casters for furniture, such as hospital beds, and more particularly to an improved assembly for removably mounting a lockable swivel caster of a known type on a hollow leg.
Rotatable or wheeled casters are well known and sockets for mounting the casters are also well known. For instance, U.S. Pat. No. 75,080 to Twining which issued Mar. 3, 1868 shows a socket for receiving the stem of a caster which is driven into the wooden leg of a bed. While many improvements have been made to this type of socket over the intervening years, generally the cylindrical stem of the caster has been free to rotate in a cylindrical hole or well in the socket mounted in the leg.
More recently, lockable swivel casters have been developed with mechanisms for locking against swiveling of the caster as well as rotation of the wheel. Examples of these are shown in U.S. Pat. Nos. 4,035,864 to Schroder which issued July 19, 1977 and 4,385,414 to Damico which issued May 31, 1983. In order to prevent rotation about the vertical axis in the locked position, it is necessary that the stem of the caster be rotatably fixed relative to the leg of the bed. As seen in U.S. Pat. No. 4,385,414 mentioned above, this is achieved by the caster having a square stem which is mounted directly in the leg of the bed. In the normal situation where the caster has a cylindrical stem and a socket is used, the socket and the stem are fixed together by drilling a hole laterally through them and inserting a pin. However, this has the disadvantages of being more difficult and costly to do and being more troublesome to remove the caster for repair or replacement.